Resonant pump using flat disc springs

ABSTRACT

A preferred embodiment of the invention described herein provides a device for raising the pressure of a volume of fluid comprising, a solenoid-operated piston and cylinder unit having a valve structure associated therewith for controlling the intake and exhaust of the fluid and a suitable electrical energy source for energizing the solenoid. The piston is supported within the cylinder by a flat disc spring that not only provides the required restoring forces, but seals the space between the piston and cylinder and effectively enlarges the working area of the piston.

United States Patent [72] Inventor Joseph S. Hollyday West Hurley, N.Y. [21] Appl. No. 799,577 [22] Filed Feb. 17, 1969 [45] Patented Mar. 30, 1971 [73] Assignee Rotron Incorporated Woodstock, NY.

[54] RESONANT PUMP USING FLAT DISK SPRINGS 12 Claims, 4 Drawing Figs.

[52] U.S.Cl 417/413 [51] Int. Cl F04b 17/04 [50] Field ofSearch 103/53,53 (A); 230/55; 310/18; 417/413, 417

[56] References Cited UNITED STATES PATENTS 1,534,829 4/1925 Behnke 103/53 GAS OUT

GAS IN 2,630,760 3/1953 Ryba 103/53 2,930,324 3/1960 Toulmin, Jr. 103/53 FOREIGN PATENTS 54,797 10/1950 France 103/53 Primary Examiner Robert M. Walker AttorneyBrumbaugh, Graves, Donahue & Raymond Patented March 30, 1971 3,572,980

2 Sheets-Sheet 1 GAS GAS OUT IN T L 4 l0 32 26 I8 2 az L4 24 v 58 O o 1& O O

IN VEN 'I ()R. JOSEPH S. HOLLYDAY BY M, Mikh his ATTDFRIVEYS Patented March 30, 1971 3,572,980

2 Sheets-Sheet 2 FIG. 4 F/G. 3

I'NVEN'IOR. JOSE PH S. HOLLYDAY Qv'-qt. his A: TOR/V575 MSONANT PUMP USING FLAT DTSK SPRINGS The use of pumps as fluid-moving devices has been a wellknown expedient 'for many years. One type of pump heretofore known comprises a piston-cylinder arrangement wherein the piston is displaced in one direction by a solenoid and is displaced in the other direction by a coil spring-biasing arrangement. Due to their structure, and particularly due to the use of a coil spring, these devices suffer certain inherent problems, i.e., the piston movement is not limited to the desired axial direction because the coil spring allows lateral, torsional and combinations of these deflections in several planes. If these deflections have a natural frequency equal to the driving frequency of the solenoid, they can create especially troublesome problems.

In addition to the deflection problem, these coil springs and their clamping assemblies are complex and costly devices that take up a substantial volume of space and are relatively heavy. Another cost factor in the manufacture of these pumps is introduced because the cylinder and piston must be manufactured to extremely close tolerances in order to keep fluid losses at a minimum.

This invention solves the above-mentioned problems by providing a pump that is not subjectto lateral and torsional deflections and is small, light, and very inexpensive to manufacture.

Briefly described, this invention comprises a piston-cylinder arrangement energized by'a suitable solenoid and wherein the piston is held by a flat disc spring functioning as the sole mechanical biasing means for the piston. The spring rate (force per unit deflection) is such that the natural frequency of operation equals the electric frequency, or twice the electric frequency, thereby providing a resonant pump. The disc spring also functions as a seal for the cylinder assembly and, therefore, adds to the economy of manufacture of the device.

In another embodiment of this invention, the piston may be retained by two such disc springs axially spaced from each other so that the second spring merely stores energy from the solenoid to be released to the fluid and also supports and controls the deflection of the piston. Since the second spring is mounted below the first, it does not form part of the cylinder enclosure or seal.

Yet another embodiment of this invention, utilizes a second piston-cylinder assembly at the other end of the solenoid in order to provide a double-acting pump. The pumps can be connected to provide either a high-pressure or high-volume output.

For a better understanding of the principles of this invention, reference is made to the following specification and the accompanying drawings, in which:

FIG. i is a cross-sectional view looking through the center of a pump constructed in accordance with this invention;

FIG. 2 is a cross-sectional view similar to FIG. 1 with portions omitted therefrom and showing a second embodiment of this invention utilizing two disc springs;

FlG. Eris a crosssectional view generally similar to FIG. 1 and disclosing still another embodiment of this invention, wherein two piston-cylinder arrangements are utilized to provide a double-acting-pump: and

FIG. '1 is a sectional view taken along the line 4-4 of FIG. 3 and looking generally in the direction of the arrows.

Referring now to H6. 1, there is shown a pump constructed in accordance with the principles of this invention and comprising a cylinder 10 having a suitable valve structure 12 associated therewith and a piston 14 having a suitable energy source such as a solenoid 16 associated therewith.

The cylinder it comprises a body member 38 having a central opening ziltherethrough surrounded by a shoulder portion 22, the purpose of which will be more fully explained hereinafter. The body member 18 is somewhat dish shaped, that is, the chamber has an extremely large diameter with a relatively small height, thus providing for a large capacity while maintaining a compact axial length.

The piston 114 also comprises a cylindrical member and has a diameter about one-half that of the cylinder thus obviating the need for the close tolerances ordinarily required in the conventional piston-cylinder arrangement. Around the outer periphery of the piston and at one end thereof is a lip portion 24 in which is seated a flat, washer-shaped disc spring 26. In order to retain the disc spring on the seat, a clamp member 2%, threaded on its internal surface, cooperates with threads on the outer surface of the piston 14 and engages the inner periphery of the disc spring 26 to clamp it against the lip 26. The outer periphery of the spring is secured to the cylinder by a clamp ring 3b which is secured to the cylinder by a plurality of fasteners 32. In order to complete the seal afforded by the spring 26, the inner and outer peripheries thereof are enclosed in U -shaped rubber rings 34.

A resonant operating condition is accomplished by matching the spring rate of the disc 26 to the mass of the moving parts such that the natural frequency of the spring-mass assembly equals the driving frequency or twice the driving frequency of the energy source. This provides for the most efficient operation of this type of pump.

The use of a disc spring as the sole biasing and piston-retaining means provides several significant. advantages. First, since there is no coil spring and since the disc is stiff in the lateral and torsional planes, the piston is not subject to unwanted deflections, second, since the disc forms part of the cylinder wall and seal, there is no need to maintain close tolerances between the piston and cylinder thereby reducing the cost of manufacture of the device; and third, since the cylinder end wall, seals, and coil spring retaining and clamping devices are done away with, the pump is extremely compact, light and simple to assemble.

A suitable valve means is provided in order to control the intake and exhaust of the fluid and comprises a valve plate 36 seated on the shoulder 22 and containing two sets of slots therethrough to form inlet and exhaust ports. The top face of the inlet port is beveled so that the fingers adjacent the slots serve as a stop means for the inlet valve 38 which comprises a plurality of flexible spring fingers. A. second valve plate 37 overlies the inlet valve 38 and comprises a plurality of slots which are 'nonnally closed by the spring fingers of the inlet valve 38. In operation, during the intake stroke, the valve fingers open and bear on the fingers on the first valve plate and allow the passage of fluid.

The exhaust valve 39 comprises a plurality of spring fingers that normally overlie the exhaust slots on the valve plate 36. During the pressure stroke, these fingers are flexed away from the slots and allow the passage of fluid.

A suitable valve plate '40 is mounted atop the valve assembly and comprises a circular member, also having intake and exhaust openings and including a central dividing wall t2 and a peripheral flange 44 that bears on the top of the valve plate 36 to clamp the valve assembly 112 to the cylinder 10.

The solenoid 16 comprises a frame member 46 carrying on its'lower end the armature 48 and which is secured to the underside of the clamp 28. The armature t8 comprises a stack of magnetic laminations having a generally rectangular configuration with a V-shaped notch located on their upper edge in order to reduce their weight. A stack of E-shaped laminations 50 of magnetic material comprises the stationary part of the magnetic circuit and are secured to the cylinder body 18 by suitable brackets 52. The middle leg M of the laminations Si) is shorter than the end legs so as to receive the armature and the flux generating coil 54.

The operation of the above-described device is as follows. When the coil 54 is energized by a suitable alternating current source, it creates a flux in the magnetic circuit thus causing the armature 48 and the piston 1 to move downwardly toward the stationary laminations 5b. This creates a pressure drop in the cylinder and allows the valve 31%; to open in order to suck the fluid into the cylinder. During the alternate current cycle, the spring 26, which has stored energy from the solenoid, moves the piston M upwardly thereby pressurizing the fluid and forcing it through the exhaust valve 39. It is to be understood that the alternating current can be biased or replaced by periodic direct current, if desired. Referring now to FIG. 2, there is shown a second embodi ment of the invention wherein like reference numerals are used to designate like parts. Cylinder comprises a cylindrical body member 18, as previously described, and has associated therewith the valve assembly 12.

The piston 14 has the lip 24 around its top face in order to receive the disc spring 26. Securing the spring 26 to the seat is an annular clamp band 56 having a threaded internal portion that cooperates with threads on the periphery of the piston; securing the spring 26 to the cylinder, there is a suitable spacer S8, fastened to the cylinder by bolts 32 to clamp the spring therebetween.

A second disc spring member 60, similar to the first, is mounted below the first member 26 and seats, on its inner periphery, between the clamp band 56 and a second clamp band 62 and, on its outer periphery, seats between the spacer 58 and a second clamp band 64. This second spring 60, of course, does not form any part of the cylinder enclosure or the fluid seal but merely stores energy from the solenoid and controls the lateral and torsional deflections of the pistons.

A third embodiment of the invention is disclosed in FIGS. 3 and 4 of the drawings wherein like reference numerals refer to like parts. The cylinder 10 comprises the body member 18 and has associated therewith the previously described valve assembly 12; the piston 14 carries the disc spring 26 in the manner described in connection with FIG. 1. A pair of plates as extend axially from the bottom face of the piston and are spaced from each other for a purpose to be explained hereinafier.

A second pump assembly, axially spaced from the first, comprises parts similar to the first assembly, namely, a cylinder 110 and valve structure 112 that cooperates with a piston 114 secured thereto by a flat disc spring 126. The piston 114 also includes a pair of plates extending from the piston in the manner previously described.

The solenoid 16 is operatively mounted between the two pump assemblies and comprises the armature ($8, stationary laminations '50 and coil 54. The stationary laminations 50 are secured to the cylinders 10 and 110 by suitable brackets 68 and 168 and include the short leg 51 about which the coil is mounted. The armature is riveted to a pair of plates 79 which extend between the pistons 14 and 114. Each plate 70 is secured to a plate 66 and 166 on the pistons 14 and 114, respectively, and which in addition to mounting the armature 48, provide force-transmitting means between the pistons.

The operation of this embodiment should be clear. As the piston 14 moves away from its associated cylinder 10, the piston 116 moves toward its associated cylinder 110. Thus, during the intake of the first piston, the second is pressurizing the fluid. During the alternate current cycle, the springs 26 and 126 move the pistons upwardly so that the piston 14 is pressurizing fluid and the piston 114 is sucking it in. By connecting the pumps in series a high pressure can be achieved and by mounting them in parallel, a high volume can be achieved.

While in the foregoing there has been disclosed several illustrative embodiments of this invention, various modifications will occur to those skilled in the art to which this invention pertains. Accordingly, it is not desired to limit the invention to the exact features disclosed, but to encompass all momfications that fall within the scope of the appended claims.

I claim:

1. A pump for pressurizing a fluid, comprising:

a first cylinder having means associated therewith for controlling the intake and exhaust of fluid;

a first piston movable relative to the cylinder for causing the intake and exhaust of the fluid in response to movement of the piston;

solenoid means operatively associated with the piston for moving the piston in a first direction from an initial posiion; I meians for coupling said solenoid means to a source of periodic electrical energy; and

disc spring means coupled between the piston and the cylinder for returning the piston to its initial position, said disc spring means having a spring rate matched to the mass of the moving parts coupled thereto and the frequency of the periodic electrical energy supplied by said source for engendering vibration of the moving parts at a resonant frequency in response to application of said periodic electrical energy.

2. A pump as defined in claim 1 wherein the diameter of the piston is substantially less than that of the cylinder.

3. A pump as defined in claim 2 wherein the disc spring means comprises a flat plate secured to the outer periphery of the piston'and to the inner periphery of the cylinder so as to form a part of the gas enclosure and also a seal therefor.

4. A pump as defined in claim 3 including a second disc spring associated with the piston and cylinder, the second disc spring being concentric with and axially spaced from the other disc spring.

5. A pump as defined in claim 1 wherein a second disc spring is associated with the piston and cylinder, the second disc spring being concentric with and axially spaced from the other disc spring.

6. A pump as defined in claim 1 wherein the solenoid means comprises an armature secured to the bottom of the piston. and a stack of E-shaped magnetic laminations carried by the cylinder to form a magnetic circuit with the armature.

7. A pump as defined in claim 6 wherein a coil is carried around the inner leg of the laminations for generating a magnetic flux in the magnetic circuits.

8. A pump as defined in claim ll having one and only one solenoid means and further comprising a second piston and cylinder spaced from the first piston and cylinder and forcetransmitting means connecting said first and second pistons to provide a double-acting pump.

9. A pump as defined in claim 8 wherein the force-transmitting means comprises at least one plate secured to both the first and second pistons.

10. The pump as defined in claim 8, wherein the second piston and cylinder are axially spaced from the first piston and cylinder.

11. The pump as defined in claim 6 and further comprising a second piston and cylinder spaced from the first piston and cylinder and force-transmitting means connecting said first and second pistons to provide a double-acting pump.

12. The pump as defined in claim 11, wherein the forcetransmitting means comprises at least one plate secured to both the first and second pistons. 

1. A pump for pressurizing a fluid, comprising: a first cylinder having means associated therewith for controlling the intake and exhaust of fluid; a first piston movable relative to the cylinder for causing the intake and exhaust of the fluid in response to movement of the piston; solenoid means operatively associated with the piston for moving the piston in a first direction from an initial position; means for coupling said solenoid means to a source of periodic electrical energy; and disc spring means coupled between the piston and the cylinder for returning the piston to its initial position, said disc spring means having a spring rate matched to the mass of the moving parts coupled thereto and the frequency of the periodic electrical energy supplied by said source for engendering vibration of the moving parts at a resonant frequency in response to application of said periodic electrical energy.
 2. A pump as defined in claim 1 wherein the diameter of the piston is substantially less than that of the cylinder.
 3. A pump as defined in claim 2 wherein the disc spring means comprises a flat plate secured to the outer periphery of the piston and to the inner periphery of the cylinder so as to form a part of the gas enclosure and also a seal therefor.
 4. A pump as defined in claim 3 including a second disc spring associated with the piston and cylinder, the second disc spring being concentric with and axially spaced from the other disc spring.
 5. A pump as defined in claim 1 wherein a second disc spring is associated with the piston and cylinder, the second disc spring being concentric with and axially spaced from the other disc spring.
 6. A pump as defined in claim 1 wherein the solenoid means comprises an armature secured to the bottom of the piston, and a stack of E-shaped magnetic laminations carried by the cylinder to form a magnetic circuit with the armature.
 7. A pump as defined in claim 6 wherein a coil is carried around the inner leg of the laminations for generating a magnetic flux in the magnetic circuits.
 8. A pump as defined in claim 1 having one and only one solenoid means and further comprising a second piston and cylinder spaced from the first piston and cylinder and force-transmitting means connecting said first and second pistons to provide a double-acting pump.
 9. A pump as defined in claim 8 wherein the force-transmitting means comprises at least one plate secured to both the first and second pistons.
 10. The pump as defined in claim 8, wherein the second piston and cylinder are axially spaced from the first piston and cylinder.
 11. The pump as defined in claim 6 and further comprising a second piston and cylinder spaced from the first piston and cylinder and force-transmitting means connecting said first and second pistons to provide a double-acting pump.
 12. The pump as defined in claim 11, wherein the force-transmitting means comprises at least one plate secured to both the first and second pistons. 